Dual voice coil motor structure in a dual-optical module camera

ABSTRACT

Dual-optical module autofocus (AF) or AF plus optical image stabilization (OIS) cameras with reduced footprint and reduced mutual magnetic interference. Some AF+OIS cameras may include a single AF actuation assembly that moves two lens barrels in unison. Some AF cameras or AF+OIS cameras may have two AF actuation sub-assemblies and associated magnets for independent AF operation of each lens barrel, the magnets shared in a manner that cancels magnetic influences of one AF actuation sub-assembly on the other AF actuation sub-assembly, thereby allowing the two lens barrels to be positioned in close proximity, saving parts and fabrication costs.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation application of U.S. patentapplication Ser. No. 15/117,189 filed Aug. 6, 2016, which was a 371application from international patent application PCT/IB2016/050844, andis related to and claims priority from U.S. Provisional PatentApplication No. 62/141,875 filed Apr. 2, 2015 and having the same title,which is incorporated herein by reference in its entirety.

FIELD

Embodiments disclosed herein relate in general to dual or multi-voicecoil motor (VCM) structures and in particular to dual-VCM structuresused in miniature dual-optical or more module cameras.

BACKGROUND

A compact (miniature) dual-optical module camera (also referred to as“dual-aperture camera”, “dual-lens camera” or simply “dual-camera”), ase.g. in a smart-phone, can be used in conjunction with appropriatecomputational photography algorithms for several purposes. These includeachieving advanced digital zoom, lowering total module height whilekeeping high performance, improving low-light performance and creatingdepth maps. In order to simplify the computational photographyalgorithms and thus reduce time and errors, it is required that the twocameras be set as closely proximate as possible. In compact cameramodules, the most ubiquitous form of achieving auto-focus (AF) and/oroptical image stabilization (OIS) is by actuating (shifting) an imaginglens (or simply “lens”) module of the camera with respect to the camerasensor(s). The most common actuator type in such cameras is the voicecoil motor (VCM). A VCM actuator includes coils, fixed (also referred toas “permanent” or “hard”) magnets and springs. When current is driventhrough a coil, an electro-magnetic (EM) Lorentz force is applied on itby the magnetic field of the magnets and the lens module changesposition. The EM force is balanced against the springs to achieve therequired position.

In dual-aperture photography, two camera modules enable taking twoimages of the same scene simultaneously. Each camera may include one ormore VCM (or other magnetic) actuator(s) for AF and OIS purposes. Whenusing VCM actuators, the VCM actuators are positioned in closeproximity. The two camera modules may have identical or differentoptical elements (lens modules/lenses). Each VCM actuator needs then toactuate its respective lens module according to the optical demands.Each VCM actuator needs to operate separately, preferably as if it werenot coupled magnetically to the other VCM actuator (i.e. as if it were astandalone module).

Two VCM actuators in close proximity may interfere with each other'smagnetic field and may not work properly. This interference limits theminimal distance between the actuators and/or requires unique magneticstructures and changes to the VCM. A small distance is advantageous forminimizing camera footprint and for simplifying computationalphotography algorithms and calculations, because it results in smallerparallax.

Known solutions to the proximity problems posed by miniaturizeddual-optical module cameras include use of off-the-shelf actuators andsome means for magnetic shielding (see e.g. PCT patent applicationPCT/IB2014/062181). The latter limits the proximity achievable in thepositioning of two actuators in a single camera. Another solutionincludes a VCM that houses two lenses that move together (see e.g. PCTpatent application PCT/IB2014/062854).

There is therefore a need for, and it would be advantageous to have waysto construct a magnetically stable structure that can house two lensmodules in close proximity to each other, and actuate each lens barrelin an independent way for AF purposes. In addition there is a need foran OIS mechanism coupled to such a structure.

SUMMARY

In various embodiments there are disclosed multi-optical module AF orAF+OIS imaging devices (cameras) and in particular dual-optical modulecameras, each dual-optical module camera having two AF actuationsub-assemblies, the cameras having improved VCM magnetic design, reducedpart numbers and reduced footprint. In each such camera, magnetsprovided for the two AF actuation sub-assemblies are shared in a mannerthat allows two lens modules to be assembled in very close proximity,removing the need for a magnetic shield therebetween.

Hereinafter, the term “lens” is used instead of “imaging lens” forsimplicity. In an exemplary embodiment, there is provided an imagingdevice comprising: a first lens module having a first optical axis andincluding a first lens carrier with a first lens carrier externalsurface, the first lens carrier having a first coil wound around atleast part of the first lens carrier external surface; a second lensmodule having a second optical axis parallel to the first optical axisand including a second lens carrier with a second lens carrier externalsurface, the second lens carrier having a second coil wound around atleast part of the second lens carrier external surface; a firstplurality of magnets surrounding the first coil, and a second pluralityof magnets surrounding the second coil, wherein the first and secondpluralities of magnets share at least one common magnet, and whereineach of the first and second plurality of magnets is associated with anauto-focus actuation of the respective lens module.

In an exemplary embodiment, the magnets of the first plurality havenorth poles pointing toward the first optical axis and the magnets ofthe second plurality have south poles pointing toward the second opticalaxis. Exemplarily, the first and second pluralities of magnets mayinclude a combined total of four to seven magnets. The magnets mayexemplarily be rigidly coupled to a frame. Each lens carrier andassociated coil may move relative its respective plurality of magnetsand the frame, wherein the movement of each lens carrier and itsassociated coil is independent of the movement of the other lens carrierand its associated coil.

In some exemplary embodiments, an imaging device may further comprise aboard having attached thereto a plurality of OIS coils, each OIS coilassociated with at least one of the magnets from the first or secondplurality of magnets, wherein the frame is movable relative to the boardin a plane substantially perpendicular to both optical axes as a resultof magnetic forces developing between at least some of the OIS coils andtheir respective associated magnets when a current is passed inrespective OIS coils. A position sensing mechanism that exemplarilyincludes at least one Hall bar may be used for sensing motion in a planeperpendicular to each optical axis and/or for sensing roll motion aroundan optical axis. The sensing of position in one direction is independentof the sensing of position in another direction.

In an exemplary embodiment, there is provided an imaging devicecomprising: a first lens module having a first optical axis; a secondlens module having a second optical axis parallel to the first opticalaxis; a lens carrier housing the first and second lens modules, the lenscarrier having an external carrier surface with a coil wound around atleast part of the external carrier surface; a plurality of magnetssurrounding the coil; and a housing frame for housing the plurality ofmagnets, the housing frame hung by springs above a board having attachedthereto a plurality of OIS coils, each OIS coil associated with at leastone of the magnets, wherein the housing frame is movable relative to theboard in a plane substantially perpendicular to both optical axes as aresult of magnetic forces developing between at least some of the coilsand their associated magnets when a current is passed in respective OIScoils, and wherein the first and second lens modules are configured toundergo simultaneous auto-focusing operations.

A position sensing mechanism that exemplarily includes at least one Hallbar may be used for sensing motion in a plane perpendicular to eachoptical axis and/or for sensing roll motion around an optical axis. Thesensing of position in one direction is independent of the sensing ofposition in another direction.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting examples of embodiments disclosed herein are describedbelow with reference to figures attached hereto that are listedfollowing this paragraph. Identical structures, elements or parts thatappear in more than one figure may be labeled with a same numeral in thefigures in which they appear. The drawings and descriptions are meant toilluminate and clarify embodiments disclosed herein, and should not beconsidered limiting in any way.

FIG. 1A shows schematically an exploded view of embodiment of adual-aperture camera having a dual VCM AF actuator disclosed herein:

FIG. 1B shows an isometric view of the camera of FIG. 1A;

FIG. 1C shows an isometric view of a first magnet set embodiment withseven magnets in the camera of FIG. 1B;

FIG. 1D shows a top view of the seven magnets of the embodiment in FIG.1C and associated pole directions;

FIG. 1E shows a top view of another magnet set embodiment with fivemagnets and associated pole directions in a camera embodiment as in FIG.1A;

FIG. 2A shows schematically an exploded view of embodiment of adual-optical module camera having a dual VCM AF+OIS actuator disclosedherein:

FIG. 2B shows an isometric view of the camera of FIG. 2A;

FIG. 2C shows an isometric view of a first magnet set embodiment ofseven magnets in the camera of FIG. 2B;

FIG. 2D shows a top view of six coils under the seven magnets of theembodiment in FIG. 2C;

FIG. 2E shows a top view of the seen magnets of the embodiment in FIG.2C on top of the six coil, and associated magnet pole directions;

FIG. 2F shows a top view of another magnet set embodiment with fivemagnets and associated pole directions in a camera embodiment as in FIG.2A;

FIG. 3A shows cross sections A-A and B-B in a dual-optical module cameradisclosed herein;

FIG. 3B shows results of a simulation of the magnetic field in the X-Yplane in a dual-optical module camera along cross section A-A;

FIG. 4A shows results of a simulation of the magnetic field in the X-Yplane in a dual-optical module camera along cross section B-B;

FIG. 4B shows a magnification of an area in FIG. 4A;

FIG. 5 shows: (A) force applied on magnet 118 a and (B) the equivalentcenter mass force and torque; (C) force applied on magnet 118 c and (D)the equivalent center mass force and torque;

FIG. 6A shows schematically an exploded view of another embodiment of adual-optical module camera having a single VCM with a combined AF+OISactuator;

FIG. 6B shows the camera of FIG. 6A in an isometric view;

FIG. 6C shows an isometric view of a magnet set embodiment of sixmagnets in the camera of FIG. 6B;

FIG. 6D shows a top view of the six magnets of the embodiment in FIG. 6Cand associated pole directions;

FIG. 6E shows a top view of another magnet set embodiment with fourmagnets and associated pole directions in a camera embodiment as in FIG.6A.

DETAILED DESCRIPTION

All figures described next are drawn in a three axis (X-Y-Z) referenceframe in which the axes are defined as follows: the Z axis is parallelto the optical axes of two lens modules and perpendicular to the surfaceof camera sensors. The Y axis is perpendicular to the optical axes ofthe two lenses and parallel to the camera sensor surfaces. The Y axis isalso perpendicular to the shortest line connecting the optical axes ofthe two lens modules. The X axis is perpendicular to the optical axes ofthe two lenses, parallel to the camera sensor surfaces and parallel tothe shortest line connecting the optical axes of the two lenses.

FIG. 1A shows schematically an exploded view of embodiment 100 of adual-optical module camera having a dual-VCM AF actuator disclosedherein. FIG. 1B shows camera 100 in an isometric view, FIG. 1C shows anisometric view of a magnet set embodiment with seven magnets, and FIG.1D shows a top view of the seven magnets of the embodiment in FIG. 1Cand associated pole directions.

Dual-optical module camera 100 includes two AF actuation sub-assemblies102 a and 102 b. Each AF actuation sub-assembly includes an optical lensmodule, respectively 104 a and 104 b, each lens module including a lenselement, respectively 106 a and 106 b, optically coupled to a respectiveimage sensor (not shown but described below). Each lens module may havedimensions as follows: a diameter in the range 6-7 mm, a height of about4 mm and a fixed focal length in the range of 4-8 mm. The two lensbarrels may be identical or may be different in some parameters such asfocal length, diameter and f#. Each lens barrel is housed in a separatelens carrier, respectively 108 a and 108 b. The lens carriers aretypically (but not necessarily) made of a plastic material. Each lenscarrier has a coil (respectively 110 a and 110 b) wound around at leastpart of an external carrier surface (respectively 111 a and 111 b). Thecoil is typically made from copper wire coated by a thin plastic layer(coating) having inner/outer diameters of respectively in the range of50-60 μm, with several tens of turns per coil such that the totalresistance is typically on the order of 10-30 ohms per coil.

Each AF actuation sub-assembly further includes a spring set, eachspring set including two (upper and lower) springs. Thus, a first springset of actuation sub-assembly 102 a includes an upper spring 112 a and alower spring 114 a, while a second spring set of sub-actuation assembly102 b includes an upper spring 112 b and a lower spring 114 b. Springs112 a, 112 b, 114 a, 114 b may all be identical, as shown in thisembodiment. In other embodiments, they may vary in shape, springconstants, dimensions and materials. Each set of springs acts a singlelinear rail that suspends the AF actuation sub-assembly. The linear railis typically flexible in one direction of motion, namely along the Zaxis (optical axis of the suspended lens), with a typical stiffness of20-40 N/m, and is very stiff along the other two axes of motion, namelyin the X-Y plane (or perpendicular to the optical axis of the suspendedlens), with a typical stiffness >500 N/m.

Camera 100 further includes a set of seven magnets (numbered 118 a-g),all housed (glued) in a single plastic or metallic frame 120. Frame 120encases magnets 118 a-g. Magnets 118 a-g may all be identical, as inthis embodiment. In other embodiments, they may vary in shape, magneticfield, dimensions and materials. The magnets arrangement is described indetail below. The spring sets of the two actuation sub-assemblies arehung on frame 120 and allow motion as described above. The two AFactuation sub-assemblies, the frame and the seven magnets form a“combined” actuation assembly referred to hereinafter as a“dual-AF-actuation” assembly.

Frame 120 is fixed onto a base 122, by glue or other means, normallymade of a plastic material. Base 122 includes openings (round holes) 124a and 124 b for two image sensors (not shown). The image sensors aretypically rectangular, with diagonal length in the range of ¼″ to ½″.The image sensors may be identical or different in size, type of sensingmechanism, etc. Each of the sensors is positioned just below of the twoactuation sub-assemblies 102 a and 102 b on a printed circuit board(“PCB”—not shown) and acquires a respective image in a known fashion.The actuation (motion) of the actuation sub-assemblies in the Zdirection allows focusing of the light coming from images at variousdistances from the camera on the image sensors. Finally, camera 100includes a shield 132, typically made from stainless steel, whichprotects all components included therein for mechanical damage, dust andstray light.

FIG. 1E shows a top view of another magnet set embodiment in whichmagnets 118 a+118 b and 118 d+118 e are joined (e.g. sintered) withpoles as shown, essentially reducing the number of magnets from seven tofive. Such “joined” magnets are known in the art, and described forexample in PCT patent application WO2014/100516A1.

FIG. 2A shows schematically an exploded view of embodiment 200 of adual-optical module camera having a combined dual VCM AF and OISactuator. FIG. 2B shows camera 200 in an isometric view, FIG. 2C showsan isometric view of a magnet set embodiment with seven magnets. FIG. 2Dshows a top view of six coils under the seven magnets. FIG. 2E shows atop view of the seven magnets on top of the six coils and associatedmagnet pole directions.

Camera 200 includes all the components of camera 100 as well asadditional components, with differences as follows: in camera 200, aframe 120′ is not fixed onto base 122 but is rather suspended on asuspension spring system comprising four springs 220 a, 220 b, 220 c and220 d (FIG. 2B). The springs are typically made of thin round wires andfirm a suspension mechanism known in the art, see e.g. co-owned U.S.patent application Ser. No. 14/373,490 to Corephotonics Ltd. Thismechanical structure is further analyzed below. In some embodiments,other types of springs (e.g. of rectangular cut or oval) may be used. Insome embodiments, more than four springs may be used. Camera 200 furtherincludes OIS motion coils 204 a-f positioned on a PCB 250 which is gluedon base 122. Coils 204 a-f are positioned under respective magnets 118a-e and apply a Lorentz force on the respective magnets. Camera 200further includes sensing elements (e.g. Hall bars) 206 a-c (FIG. 2C)that can measure a magnetic field and indicate the position of thedual-AF-actuation assembly, for example as in US 20140327965A1. Such amotion in the X-Y plane allows performance of OIS, by compensating forhand movements that shift and tilt the camera module with respect to theobject to be captured, as known in the art.

Coils 204 a-f may be operated in various actuation modes. In some suchactuation modes, currents are directed through only some of the coils.In some actuation modes, current are directed through all of the coils.As explained below, in all modes of operation there is a completedecoupling between different modes of motion, namely the two Z-directionmotions of the two lenses relative to frame 120 (or 120′) and the X-Ymotion of frame 120′ relative to the base.

FIG. 2F shows a top view of another magnet set embodiment which magnets118 a+118 b and 118 d+118 e are joined (e.g. sintered) with poles asshown, essentially reducing the number of magnets from seven to five.

Four-Wire Spring Mechanical Structure

A mechanical structure consisting of four round wires is typically usedfor in-plane motion in OIS mechanisms, see e.g. co-owned U.S. patentapplication Ser. No. 14/373,490 to Corephotonics Ltd. For wires withtypical diameter ranges of 50-100 μm typically made from metal (forexample: stainless-steel alloy) and carrying a dual AF-actuationassembly with a total mass of 0.5-1 gram, the following typical modes ofmotion are created:

Typical spring Typical Motion mode constant range frequency range X40-60 N/m 30-60 Hz Y 40-60 N/m 30-60 Hz Z ~250000 N/m ~3000-4000 Hz Rollaround X ~5 N * m/rad ~5000-6000 Hz Roll around Y ~1.25 N * m/rad~3000-4000 Hz Roll around Z ~0.001 N * m/rad ~60-100 Hz

For motion in three modes, the X mode, the Y mode and the “roll aroundZ” mode, the typical frequency range is much lower than for the otherthree modes. The physical meaning of this fact is that motion in Z mode,roll around X mode and roll around Y mode are much stiffer and areunlikely to occur under low forces like those that exist in the system(order of 0.01N).

As explained above, motion in the X-Y plane allows OIS performance. Inthe cases known in the art of a single aperture camera module (forexample in PCT/IB2014/062181), a roll motion around the Z (optical) axiswill not influence the image, since lens modules are axis-symmetricaround this axis. In the cameras disclosed herein, a roll around the Zaxis may cause distortion or shift the image, and is thus unwanted.Therefore, a cancellation method provided herein for this mode isdisclosed below.

Electrical Connectivity

Two wire electrical connections are needed per coil, for current inputand output, for each coil in the embodiments demonstrated. For camera100 and for the moving coils 110 a and 110 b in the of two AF actuationsub-assemblies, is it desired that the electrical connections not addany external limitation (i.e. external forces, friction, etc.) on themoving structure. As in typical cases (see for example patentWO2014/100516A1), springs 112 a-b and 114 a-b can covey the current. Inan embodiment, springs 112 a and 114 a may convey the current for coil110 a (in and out, respectively), while springs 112 b and 114 b mayconvey the current for coil 110 b (in and out, respectively). In anembodiment, spring 112 a may be split to two halves, such thatmechanically it serves as a single spring while each half serves as asingle electrical connection for coil 110 a. Similarly, spring 112 b maybe split to two halves, such that mechanically it serves as singlespring, while each half serves as a single electrical connection forcoil 110 b.

For camera 200, currents are needed to be further conveyed from themoving AF assembly to the stationary base 122. Springs 220 a-d may servefor this purpose as follows: springs 220 a and 220 d may convey currentsfrom AF actuation sub-assembly 102 a to base 122, while springs 220 band 220 c may convey currents from AF actuation sub-assembly 102 b tobase 122.

Magnetic and Mechanical Analysis

The VCM force mechanism is based on Lorentz's law. The Lorentz force isknown to be equal to:F=I∫dl×Bwhere I is the current in the coil, B is the magnetic field, and d{rightarrow over (l)} is a wire element. Thus, only a magnetic fieldperpendicular to the wire creates force in the desired motion direction.The magnetic field term in the Lorentz force equation is applied on thewire by the permanent magnets. In addition, from Newton's third law offorce, an equal but opposite force is applied on the permanent magnet bythe coils.

Attention is now drawn to FIG. 1C and FIG. 2C, where only the elementsactive in the magnetic circuits appear. The poles of each of the magnetsare arranged as indicated in FIGS. 1C-1D (2C-2D). Namely, the north poleis toward the positive Y direction for magnets 118 a and 118 d, towardthe negative Y direction for magnets 118 b and 118 e the north pole,toward the positive X direction for magnets 118 c and 118 f, and towardthe negative X direction for magnet 118 g.

It can be seen that for actuation sub-assembly 102 a (and in particularfor coil 110 a), the north magnetic poles are positioned inward, makingthe magnetic field flow inward. The first actuation mode to be analyzedis the actuation mode related to motion in the Z axis. If a current incoil 110 a flows in a counter clockwise direction, according toLorentz's law a force in the positive Z direction will be applied oncoil 110 a and thus on the lens carrier 108 a and lens 106 a attachedthereto. This force is independent and does not affect actuationsub-assembly 102 b, i.e. coil 110 b, lens carrier 108 b or lens 106 b.In the same manner, it can be seen that for actuation sub-assembly 102 b(and in particular coil 110 b), the magnetic field flows outward. Thus,if a current in coil 110 b flows in a clockwise direction, according toLorentz's law a force in the positive Z direction will be applied on thecoil, and thus on the lens carrier 108 b and lens 106 b attachedthereto. This force is independent and does not affect actuationsub-assembly 102 a (coil 110 a, lens carrier 108 a or lens 106 a).

FIG. 3A shows cross sections A-A and B-B in a dual-optical module cameradisclosed herein. FIG. 3B shows results of a simulation of the magneticfield in the X-Y plane along cross section A-A in FIG. 3A, explainingthe magnetic forces acting in the AF part of the actuator. Coils 110 aand 110 b are also indicated, as is the direction of current in thecoils (counter-clockwise in coil 110 a, clockwise in coil 110 b). Inthis simulation (and the simulation to follow below) we assume magnetswith dimensions of 6 mm×1.3 mm×0.6 mm, made from neodymium with magneticcoercively H_(ci)=750 kA/m.

As shown, looking at the cross product dl×B on all parts of coil 110 aand assuming a counter-clockwise direction of current, the force actingon all parts of the coil is in the positive Z direction (away from thecamera sensor). In order to reverse the force direction, the current incoil 110 a can be reversed (to be clockwise). For coil 110 b, assuming aclockwise direction of current, the force acting on all parts of the twocoils is in the positive Z direction (away from the camera sensor). Inorder to reverse the force direction, the current in coil 110 b can bereversed (to be counter-clockwise).

Moving to the second and third actuation modes (X-Y plane) used for OIS,FIG. 4A shows simulation results of the magnetic field along section B-Bof FIG. 3A, FIG. 4A shows the magnetic field in the Z direction in theX-Y plane, with indication to the position of coils 204 a-f. FIG. 4Bshows an enlarged view of the lower left section in FIG. 4A, in thevicinity of coil 204 a. In FIGS. 4A and 4B, the X and Y axes indicatethe position in X-Y plane in mm, whereas the shade of gray indicates thestrength of the magnetic field in the Z direction. The shade scale inthe two images, which corresponds to the magnetic field strength, isindicated by the bar on the right of each figure.

When an electric current is passed in coil 204 a in a clockwisedirection, a force is applied on this coil, which acts mostly in thepositive Y direction. For a coil with 24 turns, and 100 mA, separated by100 um from magnet 118 a above it, the force is equal to about 0.0055N(0.55 gram-force). FIG. 5 shows in (A) the force on magnet 118 a and (B)the reaction to this force on the center of mass of the dualAF-actuation assembly. The force on magnet 118 a is transferred in twoparts when applied on the mass center: (1) a net force of 0.0055N in thenegative Y direction will be applied on magnet 118 a and thus on allelements attached to it rigidly in the X-Y plane, i.e. on the dualAF-actuation assembly; (2) since the magnet is not positioned in thecenter of mass of the dual AF-actuation assembly, an angular torque of0.022 N-mm will be generated around the Z axis in a counter-clockwisedirection.

Similarly, when an electric current is passed under similar conditionsin coil 204 d in a clockwise direction, a 0.0055N force is applied onthis coil, which acts mostly in the positive Y direction. This forceapplies a force of 0.0055N in the negative Y direction on magnet 118 dand in turn on the dual AF-actuation assembly, and torque of 0.022 N-mmaround the Z axis in a clockwise direction. In the same manner, when anelectric current is passed in coils 204 b and 204 e in acounter-clockwise direction, a force is applied on these coils, whichacts mostly in the positive Y direction. As a reaction to these forces,a net force in the negative Y direction will be applied on magnets 118 band 118 e, respectively. Thus, for similar coils and applied currents, anet force of 0.055N in the negative Y is applied by each magnet on thedual AF-actuation assembly, and torques of 0.022 N-mm in the clockwiseand counter-clockwise directions are applied by magnets 118 b and 118 erespectively.

When an electric current is passed in coils 204 c and 204 f in aclockwise direction, a force is applied on each coil, the force actingmostly in the positive X direction. As a result, a net force in thenegative X direction will be applied on magnets 118 c and 118 f. FIG. 5shows in (C) the force on magnets 118 c and (D) the reaction of thisforce on the center of mass of the dual AF-actuation assembly. The forceon magnet 118 c is transferred in two parts when applied on the masscenter: (1) a net force in the negative X direction on the center ofmass of the dual AF-actuation assembly; (2) since the force in the Xdirection acting magnet 118 c is balanced around the center of rotation,no torque will be created.

Motion Control in the X-Y Plane

Hall sensor 206 a is positioned below magnet 118 g, which has polesoriented along the X axis. Thus, this sensor may measure changes in themagnetic field caused by motion in the X direction. Hall sensors 206 band 206 c are positioned respectively below magnets 118 b and 118 e,which have poles oriented along the Y axis. Thus, these sensors maymeasure changes in the magnetic field caused by motion in the Ydirection. If the motion is only in the X or the Y direction, or in anycombined direction of the two, measurements of Hall-bar sensors 206 band 206 c should be equal. However, if any roll-around-Z-axis motionoccurs, since Hall-bar sensors 206 b and 206 c are positioned along thediagonal of a rectangle, the measurement in these sensors should vary.That is, the roll-around-Z-axis motion can be detected, looking at thedifference between the measurements of Hall-bar sensors 206 b and 206 c.

Using a combination of the six coils 118 a-e can create force in the X-Yplane and torque around the Z axis such that the desired motion isachieved, namely creation of X-Y motion as needed for OIS and removal ofany unwanted Z-axis-roll.

In summary, the magnet arrangements disclosed herein and their methodsof use advantageously allow increasing the proximity of adjacent VCMs,providing savings of at least a width of a magnet+two mechanicalshields+a magnetic shield greater than 1.5 mm (out of ˜10 mm). Eachreduction of 1 mm in the separation of VCMs can reduce computationaltime by ˜10%.

Simplified Camera with Unified AF

FIG. 6A shows schematically an exploded view of embodiment 600 of adual-optical module camera having a single VCM with a combined AF+OISactuator. FIG. 6B shows camera 600 in an isometric view. FIG. 6C showsan isometric view of a magnet set embodiment with six magnets. FIG. 6Dshows a top view of six coils under the six magnets. FIG. 6E shows a topview of an embodiment with six coils under four magnets.

Camera 600 is similar to camera 200 and includes similar components,except for a single AF-actuation assembly for performing simultaneous(in unison) auto-focusing of the two lenses (instead of the two AFactuation sub-assemblies 102 a and 102 b in camera 200 that performseparate auto-focusing on each lens). Camera 600 further includes asingle OIS mechanism. Camera 600 is suited tier the cases in which thetwo lens modules are identical, or at least have equal focal length,which allows focusing to the same distance.

Camera 600 includes two optical lens modules, respectively 604 a and 604b, each lens module including a lens element, respectively 606 a and 606b, optically coupled to a respective image sensor (not shown). Each lensmodule may have dimensions as follows: a diameter in the range 6-7 mm, aheight of about 4 mm and a fixed focal length in the range of 4-8 mm.The two lens barrels are identical in their focal length and may becompletely identical or different in some aspects such as diameter orF#. The two lens barrels are housed in a single lens carrier 608. Thelens carrier is typically made of a plastic material. The lens carrierhas a coil 610 wound around at least part of an external lens carriersurface 611. The coil is typically made from copper wire coated by athin plastic layer (coating) having inner/outer diameters ofrespectively in the range of 50-60 μm, with several tens of turns, suchthat the total resistance is typically on the order of 10-30 ohms.

The AF actuation sub-assembly further includes a spring set 602,including two (upper and lower) springs, 612 and 614. Springs 612 and614 may be identical, as shown in this embodiment. In other embodiments,they may vary in shape, spring constants, dimensions and materials. Theset of springs acts a single linear rail that suspends the AF actuationsub-assembly. The linear rail is typically flexible in one direction ofmotion, namely along the Z axis (optical axis of the suspended lens),with a typical stiffness of 20-40 N/m, and is very stiff along the othertwo axes of motion, namely in the X-Y plane (or perpendicular to theoptical axis of the suspended lens), with a typical stiffness >500 N/m.

Camera 600 further includes a set of six magnets (numbered 618 a-f), allhoused (glued) in a single plastic or metallic “housing” frame 620.Magnets 618 a-f may all be identical, as in this embodiment. In otherembodiments, they may vary in shape, magnetic field, dimensions andmaterials. The magnets arrangement is shown FIG. 6C. The spring sets ofthe AF actuation sub-assembly are hung on frame 620 and allow motion asdescribed above. The AF actuation sub-assembly, the housing frame andthe six magnets form a single AF-actuation assembly. Housing frame 620is suspended on a suspension spring system comprising four round springs620 a, 620 b, 620 c and 620 d (FIG. 6B), which may be similar to springs220 a-d above. The AF actuation sub-assembly and the four springs form acombined AF+OIS actuation assembly. Camera 600 further includes OISmotion coils 604 a-f positioned on a PCB 650 glued on base 622. Coils604 a-f are positioned under respective magnets 618 a-f and apply aLorentz force on the respective magnets. Camera 600 further includessensing elements (e.g. Hall bars) 606 a-c (FIG. 6C) that can measure amagnetic field and indicate the position of the combined AF+OISactuation assembly in X-Y plane. Such a motion in the X-Y plane allowsperformance of OIS, by compensating for hand movements that shift andtilt the camera module with respect to the object to be captured, asknown in the art.

Coils 604 a-f may be operated in various actuation modes. In some suchactuation modes, currents are directed through only some of the coils.In some such actuation modes, current are directed through all of thecoils. In all modes of operation there is a complete decoupling betweendifferent modes of motion, namely between each of the two Z-directionmotions of the two lenses relative to frame 620 and the X-Y motion offrame 620 relative to the base.

FIG. 6F shows a top view of another magnet set embodiment in whichmagnets 618 a+618 b and 618 d+618 e are joined (e.g. sintered)essentially reducing the number of magnets from six to four.

The operation of AF and OIS mechanisms in camera 600 is essentiallysimilar to those described for cameras 100 and 200, both mechanicallyand magnetically.

While this disclosure has been described in terms of certain embodimentsand generally associated methods, alterations and permutations of theembodiments and methods will be apparent to those skilled in the art.The disclosure is to be understood as not limited by the specificembodiments described herein, but only by the scope of the appendedclaims.

What is claimed is:
 1. An imaging device comprising: a) a first lensmodule having a first optical axis and comprising a first lens carriersurrounded at least partially by a first plurality of magnets; b) asecond lens module having a second optical axis parallel to the firstoptical axis and comprising a second lens carrier surrounded at leastpartially by a second plurality of magnets; and c) a plurality ofoptical image stabilization (OIS) coils, rigidly coupled to each other,each OIS coil associated with at least one of the magnets of the firstor second plurality of magnets, wherein the first and second pluralityof magnets are rigidly coupled to each other, wherein each lens moduleis movable relative to both pluralities of magnets along its respectiveoptical axis, wherein the movement of each lens module along itsrespective optical axis is independent of the movement of the other lensmodule along its respective optical axis, and wherein the first andsecond pluralities of magnets are movable relative to the OIS coils in aplane substantially perpendicular to both optical axes.
 2. The imagingdevice of claim 1, configured to perform focus and/or autofocus.
 3. Theimaging device of claim 1, wherein the first and second pluralities ofmagnets are movable relative to the OIS coils to perform OIS.
 4. Theimaging device of claim 1, wherein the magnets of the first pluralityhave north poles pointing toward the first optical axis and the magnetsof the second plurality have south poles pointing toward the secondoptical axis.
 5. The imaging device of claim 1, wherein the first andsecond pluralities of magnets include a combined total of four to sevenmagnets.
 6. The imaging device of claim 1, further comprising a positionsensing mechanism for sensing motion in two directions in a planeperpendicular to the optical axes, the position sensing in one directionbeing independent of the position sensing in the other direction.
 7. Theimaging device of claim 6, wherein the position sensing mechanismincludes at least one Hall bar.
 8. The imaging device of claim 6,further comprising a position sensing mechanism for sensing roll motionaround an optical axis.
 9. The imaging device of claim 8, wherein theroll motion sensing mechanism includes at least one Hall bar.
 10. Theimaging device of claim 1, wherein at least one of the magnets from thefirst and second plurality of magnets share at least one common magnet.11. An imaging device comprising: a) a first lens module having a firstoptical axis and comprising a first lens carrier surrounded at leastpartially by a first plurality of magnets, and a first AF coilassociated with at least one magnet of the first plurality of magnets toprovide a first AF movement; and b) a second lens module having a secondoptical axis parallel to the first optical axis and comprising a secondlens carrier surrounded at least partially by a second plurality ofmagnets, and a second AF coil associated with at least one magnet of thesecond plurality of magnets to provide a second AF movement; and c) aplurality of optical image stabilization (OIS) coils, each OIS coilassociated with at least one of the magnets of the first or the secondpluralities of magnets, wherein each lens module or lens carrier ismovable to create focus or autofocus (AF), wherein the movement of eachlens module or lens carrier is independent of the movement of the otherlens module or lens carrier, and wherein first and second pluralities ofmagnets include together seven magnets, wherein the first and secondpluralities of magnets are movable relative to their associated OIScoils in a plane substantially perpendicular to both optical axes.